The fluorescence of pHrodo dye dramatically increases as pH decreases from neutral to acidic, making it an ideal tool to study phagocytosis and its regulation by drugs and/or environmental factors. Outside the cell, the dye is non-fluorescent, which eliminates the need for wash steps and quencher dyes. Once internalized, the dye fluoresces brightly within the acidic environments of endosomes and lysosomes, enabling rapid assay development and certainty of results when investigating phagocytic pathways and their regulation by drugs and/or environmental factors. As such, pHrodo dye conjugates can be used in plate readers, fluorescence microscopy imaging, and flow cytometry applications.

The pHrodo Red S. aureus BioParticles Conjugate for Phagocytosis (Cat. No. A10010) offers fast and accurate assay results. pHrodo Red dye conjugates are non-fluorescent outside the cell but fluoresce bright red in phagosomes. The pHrodo Red E. coli BioParticles Conjugate for Phagocytosis (Cat. No. P35361) detects phagocytosis and endocytosis, offers reduced signal variability and improved timing in sensitive experiments, and can be used in multiplex applications with a wide variety of blue, green, and far-red dyes and reporters such as GFP, Fuo-4, calcein, NucBlue, CellEvent Caspase 3/7 green, Mitosox Green, and Mitotracker Deep Red, among many others. The optimal absorption and fluorescence emission maxima of the pHrodo Red BioParticles Conjugate is approximately 560/585 nm, respectively. However, the fluorophore is readily excited with the 488-nm argon-ion laser installed on most flow cytometers.

The pHrodo Red E. coli BioParticles Phagocytosis Kit (Cat. No. A10025) for flow cytometry is designed for rapid and convenient measurement of phagocytic activity in whole blood samples by flow cytometry. The kit includes all the reagents required for assessing particle ingestion and red blood cell lysis.

pHrodo Deep Red dye is a low-background pH sensor dye that shows no signal in neutral conditions and only fluoresces in acidic environments. pHrodo Deep Red dye enables better discrimination of internalized cargo from outside the cell because it has an approximate pKa of 5 and does not fluoresce until it enters the late endosome and lysosome. pHrodo Deep Red dye can be detected using a Cy5 fluorescent filter set and has been validated for use in a variety of applications, including flow cytometry, fluorescent microscopy, high content analysis (HCA), and high throughput screening (HTS). It can also be multiplexed with a wide variety of blue, green, and red dyes and reporters such as GFP and RFPs, Mitosox Green or Red, CellEvent Caspase 3/7 Green or Red, NucBlue, or TMR, among many others.

pHrodo Deep Red E. coli BioParticles Conjugate for Phagocytosis (Cat. No. P35360) is a no-wash, low background, fluorogenic reagent developed for the study of phagocytosis in a live cell system. This conjugate is non-fluorescent outside the cell but fluoresces dark red in phagosomes. The low pKa of the pHrodo Deep Red E. coli BioParticles Conjugate eliminates non-specific signal from non-internalized cargo and only turns on in late endosomes and lysosomes.

The pHrodo Green dye conjugates, like pHrodo Red and pHrodo Deep Red dye conjugates, offer faster and more accurate results than any other phagocytosis assay. pHrodo Green conjugates are non-fluorescent outside the cell at neutral pH but fluoresce bright green at acidic pH, such as that of phagosomes. Use the ready-made pHrodo Green S. aureus BioParticles Conjugate (Cat. No. P35367) and pHrodo Green Zymosan BioParticles Conjugate (Cat. No. P35365) for Phagocytosis in imaging, HCA, HTS, and flow applications.

These pHrodo conjugate products include enough reagent to perform 100 tests when using 100 μL in each well of a 96-well plate, and they can be multiplexed with a wide variety of blue, red, and far-red dye reporters such as Mitosox Red, CellEvent Caspase 3/7 Red, NucBlue, RFPs, and Mitotracker Deep Red, among many others.

pHrodo Red Zymosan BioParticles Conjugate (Cat. No. P35364) is also available, and pHrodo Green dye is available as a conjugate of E. coli BioParticles (Cat. No. P35366).